Membrane keyswitch

Abstract

The present invention is directed to a flexible, thin plastic film membrane switch in which a plastic housing houses an individual switch. The switch includes a flexible membrane which has a pair of unconnected, interleaved conductive patterns which extend over two elongated arms, each of which has an aperture through the conductive pattern. A conductive terminal is passed through each of the apertures with its sides making electrical connection with the associated conductive pattern and to lock the flexible membrane in place in a chamber of the housing of the switch. The upper portion of the flexible membrane then passes over a curved rib and is reverse bent back over the top of the terminals. A spacer formed by a piece of thin, plastic film material with a rectangular aperture in it is secured to an electrically-conductive plate to provide the necessary spacing between the conductive patterns on the membrane and the conductive plate. The flexible membrane, the spacer and the conductive plate are preferably all sealed together so that they may be handled as one complete unit. Indicator lights may be inserted into a second chamber of the switch housing through apertures in the bottom of the housing. A flexible touch panel is then inserted over the upper portion of the reverse-bent flexible membrane to complete the switch.

What is claimed is: 
     
       1. A membrane switch comprising an electrically insulating housing having a top and a bottom, a first chamber with at least one walled cavity therein and a plurality of passageways in communication with said cavities which extend through said bottom of said housing, a thin, flexible membrane including a plurality of elongated legs each of which have an aperture therethrough, a plurality of unconnected electrically conductive patterns on a pattern area of said membrane, each pattern of which includes an elongated conductor strip which extends over one of said legs, a plurality of electrically conductive terminals each having a terminal end which is inserted into one of said passageways so that said terminal end passes through an aperture in one of said elongated legs and projects through the bottom of said housing, the dimensions of said terminals being such that they are wedged into their associated passageways and the associated elongated leg is trapped between the walls of the associated cavity and said terminal, a conductive plate in said housing, said flexible membrane being bent so as to position said pattern area of said membrane over said conductive plate and a spacer member having a window therein which is positioned between said pattern area and said conductive plate. 
     
     
       2. A membrane switch as claimed in claim 1 wherein said membrane, spacer and conductive plate are all secured together as a unit prior to assembly of the switch. 
     
     
       3. A membrane switch as claimed in claim 1 wherein said housing has a second chamber and said bottom of said housing has at least one housing aperture therein which leads to said second chamber and said switch further comprises an overlay touch panel which is opaque except for a clear section which overlays said second chamber and at least one light means inserted into said second chamber through one of said housing apertures. 
     
     
       4. A membrane switch as claimed in claim 1 further comprising two trapezoidal-shaped blocks each of which extends from one side of said housing and two trapezoidal-shaped recesses, each of which is formed in two other sides of said housing. 
     
     
       5. A membrane switch as claimed in claim 2 wherein said housing has a second chamber and said bottom of said housing has at least one housing aperture therein which leads to said second chamber and said switch further comprises an overlay touch panel which is opaque except for a clear section which overlays said second chamber and at least one light means inserted into said second chamber through one of said housing apertures. 
     
     
       6. A membrane switch as claimed in claim 5 further comprising two trapezoidal-shaped blocks each of which extends from one side of said housing and two trapezoidal-shaped recesses, each of which is formed in two other sides of said housing. 
     
     
       7. A membrane switch comprising an electrically insulating housing having an open top and a closed bottom, a first chamber with at least one walled cavity therein and first and second passageways in communications with said cavities which extend through said bottom of said housing, said housing further having at least one curved rib which extends from said cavities toward said top of said housing, a thin, flexible membrane including first and second elongated legs each of whiich have an aperture therethrough, first and second interleaved, unconnected electrically conductive patterns on a pattern area of said membrane, each pattern of which includes an elongated conductor strip which extends over one of said legs, first and second electrically conductive terminals each having a terminal end which is inserted into a respective one of said first and second passageways so that said terminal end passes through an aperture in one of said elongated legs and projects through the bottom of said housing, the dimensions of said terminals being such that they are wedged into their associated passageways and the associated elongated leg is trapped between the walls of the associated cavity and said terminal, a conductive plate in said housing, said flexible membrane having a reverse bend therein which positions said pattern area of said membrane over said conductive plate and said terminals, and at least a portion of said membrane intermediate said pattern area and apertures in said elongated legs is positioned to engage said ribs, said conductive plate being positioned intermediate said pattern area and said terminals and a spacer member having a window therein which is positioned between said pattern area and said conductive plate. 
     
     
       8. A membrane switch as claimed in claim 7 wherein said membrane, spacer and conductive plate are all secured together as a unit prior to assembly of the switch. 
     
     
       9. A membrane switch as claimed in claim 8 wherein said housing has a second chamber and said bottom of said housing has at least one housing aperture therein which leads to said second chamber and said switch further comprises an overlay touch panel which is opaque except for a clear section which overlays said second chamber and at least one light means inserted into said second chamber through one of said housing apertures. 
     
     
       10. A membrane switch as claimed in claim 9 further comprising two trapezoidal-shaped blocks each of which extends from one side of said housing and two trapezoidal-shaped recesses, each of which is formed in two other sides of said housing.